Quadrupolar Interaction with Zeolite and Pressure Swing Adsorption in Portable Medical Oxygen Concentrators for Breathing of Covid-19 and COPD Patients

Pressure swing adsorption (PSA) technology is used in medical oxygen concentrators for selective adsorption of nitrogen under pressure from air to produce oxygen-enriched air for breathing. The functional material in oxygen concentrators is aluminosilicate zeolite like Li-13X, 5A (LTA) with a relatively high Al-content. It selectively adsorbs nitrogen from the air into their molecular sieves due to the strong quadrupolar interaction between the adsorbed nitrogen and the electrical field of the charge balancing non-framework exchangeable cations of aluminosilicate zeolites. In an oxygen concentrator, two adsorbent vessels packed with the zeolite working alternately in a cyclic process are used for a near-continuous production of the oxygen-enriched air.